Energy expenditure in resting state is almost equal to Basal metabolic rate i.e. the minimum energy expenditure for the body to exist. Basal metabolic rate is related to both Body surface area and Lean body mass. However it appears to be more closely related to Lean body mass. Lean body mass is the total mass of the body minus the fat. Total daily energy expenditure is made up of resting energy expenditure and activity energy expenditure. Resting Energy Expenditure (REE) = BMR + thermal effect of food Activity Energy Expenditure (AEE) is the energy expended by the body in movement including both energy dependent in sedentary or obligatory activities and that expended in discretionary activity. It makes up 20-40% of the total energy required. TEE = REE + AEE